Hydraulic guiding boom for a rock drill



Aug. 19, 1969 R. STROM 3,462,103

HYDRAULIC GUIDING BOOM FOR A ROCK DRILL Filed Dec. 8, 1966 I2 If 13 I4 u mum I 24 j Z 22! INVENTOR. ROL F STROM A Tram/ x United States Patent US. Cl. 248-13 2 Claims ABSTRACT OF THE DISCLOSURE Arrangement for rock drill booms to maintain seat direction the same regardless of boom movements by interposing hydraulic motors between boom and support and boom and seat. Conduits interconnect the hydraulic motors for flow of fluid to maintain seat direction regardless of boom movement and to simplify drilling of parallel bores.

A common method for breaking a mine or other tunnel involves drilling of a plurality of parallel bores very near to each other in the middle of the end wall of the tunnel. A portion of these so called opening bores are charged while the other portion is leftuncharged. Parallelism of the opening bores is a condition for succesful blasting. In addition to the said bores, bores are drilled on the remaining portion of the cross sectional area of the mine tunnel, the spacing of which bores is greater and the accurate parallelism of which is not necessary.

In rock drilling it is common to utilize a hydraulic boom for supporting and guiding the rock drilling machine and its feeding device. The boom has here several possibilities for movement, it can turn both in the vertical and the horizontal planes and its length can be varied.

The seat of the drilling machine at the end of the boom can be guided to be turned with respect to all three space axes (normally two). In addition to this the position of the apparatus attached to the machine seat can be varied with respect to the seat. The boom and the seat can be provided with all or a part of the said degrees of freedom. When the boom is turned both the position and the direction of the seat are changed. If it is desired that the seat should maintain its direction when transferred from one bore to another, it must be directed anew. This new directing operation can be avoided by means of forcible guidance of the seat. In at present known solutions of this problem this has been realized mechanically with the help of two parallel rails, which are connected by means of a scissor arrangement.

The present invention relates to an automatically operable parallel guiding arrangement of a hydraulic guiding boom for a rock drilling machine. T o the hydraulic turning elements of the seat there are connected hydraulic pump means, which receive their power from the movements of the boom and which pump such amounts of oil to the turning elements of the seat that the seat will maintain its direction when turning, either with theoretical accuracy or approximately, depending on the requirements of accuracy which determine the design.

An embodiment of the invention is more fully described in the following with reference to the accompanying drawing in which are shown only the control and guidance of the movements taking place in the vertical plane, while in practice a similar system is provided for the movements taking place in the horizontal plane.

The drawing shows a boom 1 attached to a support by means of an articulation 2. The boom is turned in the vertical plane by the piston rod 6 of a piston 5, which 3,462,103 Patented Aug. 19, 1969 ice by means of an articulation 7 is attached to the boom 1, and which moves in a cylinder 4, which by means of an articulation 3 is attached to the support.

In that end of the boom where the articulation 7 is situated, there is also located a seat 8 for a drilling machine or similar working machine, the seat being attached to the boom 1 through an articulation 9. The seat 8 is turned with respect to the boom 1 by a piston rod 13 of a piston 12, the piston rod 13 being attached to the seat through an articulation 14 and moving in a cylinder 11 attached to the boom 1 through an articulation 10, which articulation 14 is situated in spaced relationship with respect to the articulation 9 connecting the seat 8 and the boom 1, thus forming an articulate arm 15.

At the end of boom 1 opposite to articulation 9 and at the other side of articulation 2 there is attached through an articulation 16 a piston rod 17 operated by a piston 20 moving in a cylinder 19 attached to an articulation 18 through a support. In the embodiment described fluid is fed by means of a pump 21 from a container 22 through conduits 23 and 24 to control valves 25 and 26 for the cylinder 4 and 11, 19 respectively, the fluid being passed through pairs of conduits 27 and 28 to the respective cylinders.

The operation of the apparatus is as follows: at commencement of drilling the seat 8 is directed by introducing fluid through valve 26 to cylinders 11 and 19, whereupon the valve is shut. When the first drill hole is finished and it is desired to drill another hole above the first one, which later hole is parallel to the first mentioned hole, fluid is introduced through valve 25 to cylinder 4 beneath its piston 5, whereby boom 1 rises upward. Simultaneously the piston 20 in cylinder 19 moves downward and forces fluid into cylinder 11 below its piston 12, whereby its piston rod 13 moves forward and thereby maintains the seat 8 in its original direction. At transfer of boom 1 the seat 8 thus always is maintained parallel to the direction originally given to the same.

If during drilling the support gives in, the apparatus looses its original position whereby the original adjusted direction of the seat 8 also is changed. In this case it is necessary to carry out a similar directing of the seat as at the commencement of drilling. By operating valve 26 fluid is fed to cylinders 11 and 19 through a pair of conduits 28 until the seat has assumed its desired direction, whereat valve 26 is shut. Thereafter only valve 25 again is used for adjustment of the apparatus for drilling of new parallel holes, the seat 8 maintaining its direction all the time.

Cylinders 11 and 19 are hydraulically connected to each other by having the spaces above the pistons connected to each other as well as the spaces beneath the pistons. When the positions of boom 1 in the vertical plane is changed by means of cylinder 4, the proportion between the volumes above and beneath the piston in cylinder 19 is changed, and by virtue of the hydraulic connection also the proportion between the volume above and beneath the piston in cylinder 11 is changed, but in the opposite direction, so that the direction of seat 8 remains unchanged.

The above described preservation of direction can be made exact if the cylinders 11 and 19 are connected so that cylinder 11 also is shortened when cylinder 19 is shortened. In this case, however, the space beneath the piston in cylinder 19 must be connected to the space above the piston in cylinder 11, and the space above the piston in cylinder 19 must be connected to the space beneath the piston in cylinder 11, in which case the cylinders must be provided with throughgoing piston rods. In practice the accuracy achievable with common cylinders provided with not-throughgoing piston rods in suflicient.

What I claim is:

1. A rock drill machine comprising a hydraulic guiding boom, an articulation attaching such boom to a support, a first hydraulic cylinder means having a piston for moving said boom, a seat, an articulation attaching said boom to said seat, a second hydraulic cylinder adjacent the seat end of said boom and attached to said boom through an articulation, said second cylinder having a piston rod, said piston rod being attached to said seat at a point spaced with respect to the articulation connection between said seat and said boom, 2. third. cylinder, an articulation joining said third cylinder to said support, said third cylinder having a piston and piston rod extending therefrom, an articulation joining said piston rod of said third cylinder to said boom, said second and third cylinders being formed with spaces therein at either sides of the pistons therein, conduit means connecting a space in one of said cylinders with a space in the other of said cylinders and conduit means connecting the other space in one of said cylinders with the other space in the other of said cylinders, said conduit means being formed to provide for the flow of hydraulic fluid between said spaces of said cylinders whereby movement of the pistons in said cylinders takes place in similar manner to maintain the References Cited UNITED STATES PATENTS 2,606,078 8/1952 Brock 182-2 3,179,267 4/1965 Bliss 182-2 X 3,226,064 12/1965 Thompson l73-43 X FOREIGN PATENTS 1,189,002 9/1959 France.

20 ERNEST R. PURSER, Primary Examiner U.S. c1. X.R. 173-43; 182-2 

